Question about removing push pull pot for a single pot

I want to remove my MKIV output pot and replace it with a single 250K.

WHY!
The reason is that I am keeping this amp forever and I am never going to record out. In fact I don't believe in it. I think I have an issue with this pot so I am going to simplify it while I am changing it.

I have attached a picture with the pot in question. As you can see there is a jumper wire on the left 2 poles. I have looked and the black and grey wire go to the same location on the PCB. The blue wire cuts across the PCB near the rear.

So .. if I put in a single pot, attached the black wire to the left, the grey wire to the center, and just remove the jumper and the blue wire this should function just like a single?

It looks that way to me. I was wondering if anyone with a little more experience can verify my logic.

Here is an image of said pot.
https://drive.google.com/open?id=0B-lzQ10ZRJzzS0t6SkV1bHJUcU0

Thanks in advance,
Donnie

Hi Donnie,

I think that you speak about the master volume labelled "output level 250K" on the schematic of the MKIV. When you pull it, it
activates the "silent" mode, muting the input of the power stage, and you do not want that option anymore : Am I right ?

If the red jumper and the blue wire are the wires that goes from the circuit to the shorting pull switch of the pot, you just have to
remove them, in order to disable the "pull silent shorting" mode forever. The black is probably the GND of the pot, and the grey is
the signal side : these should be left stock, as they control volume.

Since I do not have a MKIV on hand to check too, I'd suggest that you have a test to valid what I am writing, if you have not already done it...
If all is OK and work as expected, so yes you can change that pot for a classic 250KA (log) potentiometer.

Moreover, for the occasion, you can test an improvement in progressivity of that master volume control, if you like.

Stock, that pot acts as a variable resistor shunting more or less the signal to ground in accordance with its setting : this is not
progressive at all, like I noticed it on my MKIIA and MKIIB amps that were also wired stock like that.

Just wire that pot as a conventional volume pot, adding a supplementary signal wire on top of pot and re-routing the wiper wire. You
will notice a neat improvement in volume control spread. You may experience a very little brilliance loss doing that, so if you notice
it, just add a 22 to 47pF capacitor on the pot between top and wiper. On my MKIIA and B, this cap was unecessary.

I traced below a schematic showing the described modification :



A+!